Development of a noninvasive method to measure intravascular and intracardiac pressure differences using magnetic resonance imaging.

ABSTRACT

PURPOSE: We developed a noninvasive method using magnetic resonance (MR) imaging to measure differences in intravascular and intracardiac pressure, and we investigated the feasibility of the method's use in a pulsatile flow phantom and human studies. METHODS: We measured 3 velocity components using phase contrast MR imaging on a 1.5T MR scanner, used velocity data in Navier-Stokes equations to obtain pressure gradients, and directly integrated the in-plane pressure gradients to calculate pressure differences. To validate our method, we compared the pressure differences obtained by our method with the theoretical values obtained from an axisymmetric model of arterial stenosis. We also estimated the pressure differences in glass-tube phantoms simulating various vascular pathologies and in the left ventricle and aortic arch of a normal volunteer as clinical application. RESULTS: The pressure differences obtained by our method agreed well with theoretical values obtained using the straight-tube phantom with stenosis of 45%, but we observed some differences when stenosis was 65%. We clearly observed variations in pressure differences at specific locations at various phases of a cardiac cycle in both phantom and human studies. CONCLUSION: This method appears useful for measuring intravascular and intracardiac pressure differences.